My main photo-sharing thingy is Multiply, which a lot of people haven't heard of and that's because it mainly populated by my family and friends in the Philippines and frankly, I was happy to keep it that way.
The main thing I've learned from social networking is that the "social" is just as important as the "network". You can network meaninglessly with as many people you don't know as you want on MySpace, on the off chance that someday you will need to tell all these strangers that you've published your book. But there's nothing like a network that actually interacts with you - it takes years of blogging to get more than four comments (unless you join the Nude Blogging Movement, and then you get an instant fan base).
I find Multiply the most rewarding because it's where my "social" is ... I only have to put one silly photo up of my husband and within seconds I have 27 pithy comments from my best friend in Washington and 27 comments from my brothers and sisters in Manila (there are many of us), discussing in detail every aspect of my husband's nose, ears, hair, etc.
It's very rewarding (unless you're my husband).
Anyway, my Facebook contacts may have already noticed that I have increased activity on Facebook. This is because my Multiply friends are slowly moving to Facebook. So now I have to go on Facebook to leave insults on their albums. Boo!
Meanwhile, one of my fave YA authors John Green (Abundance of Katherines) posted this fab link imagining HAMLET's newsfeed on Facebook!
AND here's an image of VP hopeful Sarah Palin that I took off the facebook page of Maureen Johnson (Suite Scarlet, 13 Little Blue Envelopes). Yup that's a bear. And yup, that's a giant crab. It really focuses the mind on the coming US elections.
THESE are the things that make all that wasted time on Facebook seem worthwhile.